Hi!
I am trying the jit.c example (from Chapter 6) for the jit-read-queue function:
int scull_read_queue(char *buf, char **start, off_t offset,
int len, int *eof, void *data)
{
/* delay one second (or the chosen value), before printing */
/* unsigned long j = jiffies + jit_delay * HZ; */
wait_queue_head_t wait;
init_waitqueue_head (&wait);
interruptible_sleep_on_timeout(&wait, jit_delay*HZ);
*eof = 1;
return jit_print(buf);
}
I rewrote the program so that it only has this function and other
required functions.
Source and OOPS log:
http://www.geocities.com/cyborg4k/postjit.c
http://www.geocities.com/cyborg4k/oops.log
I am running Slackware 9.1 (kernel 2.4.22) on an Intel PII with 128 MB
RAM for this program testing. I compile the source file using:
#gcc -O2 -DMODULE -D__KERNEL__ -I/lib/modules/`uname -r`/build/include
-c postjit.c
Loading and unloading the module works. But, when I do "cat
/proc/jitqueue", I get an OOPS error message with the 2.4.22 kernel.
But, the output gets printed when I tested with a 2.6.0 kernel. I am
still learning about ksymoops and haven't got it to work yet.
The OOPS message gave the EIP as c01156b9.
I tried to see what is present near this address in /proc/ksyms (hope
my approach is correct :)), and it showed:
c0115630 interruptible_sleep_on
c0115690 interruptible_sleep_on_timeout
So, I am guessing there is some problem in the way the kernel handles
the interruptible_sleep_on_timeout?
I would appreciate if you can tell me why this is happening and how
best I can learn to debug the oops messages and trace/understand the
kernel control flow. Chapter 04 debugging techniques does not explain
elaborately with sufficient examples on debugging.
Sorry for the long e-mail. I wanted to give as much information as possible.
Thanks,
K Shakthi
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